The Crystallography of Metal Halides formed within Single Walled Carbon Nanotubes

The crystal growth behaviour and crystallography of a variety of metal halides incorporated within single walled carbon nanotubes (SWNTs) as determined by high resolution electron microscopy (HRTEM) is described. Simple packed structures, such as the alkali halides form related structures within SWNTs that are integral atomic layers in terms of their thickness. An enhanced HRTEM image restoration technique reveals precise data concerning lattice distortions present in these crystals. More complex structures formed within SWNTs, such as those derived from 3D complex, layered and chain halides form related crystal structures within SWNTs. In narrow (i.e. 1.6nm diameter) SWNTs, these halides form structures that consist of individual 1D polyhedral chains (1D-PHCs) derived from the corresponding bulk halides within SWNTs. In the case of the 3D complex and layered halide structures, the polyhedral chains form with lower coordination than in the bulk. Molecular halides also form within SWNTs but these are frequently disordered and do not readily form organised structures within SWNTs.